Preparation and low field magnetoresistance of double layered manganite La1.4Ca1.6Mn2O7

Double layered manganite of La1.4Ca1.6Mn2O7 (DLCMO) was prepared using solid state reaction method and had a metal-insulator transition temperature (TMI) of 125 K. The short range 2D-feerromagnetic ordering (TC2) starts growing when T<168 K and it gets converted into 3D-ferromagnetic ordering (TC1) at 114 K. Low field magnetoresistance (MR) behaviour of the DLCMO was investigated and compared with an infinite layered manganite La0.7Ca0.3MnO3 (LCMO). For DLCMO, in the temperature range between TC1 and TC2, the MR showed a gradual increase with the magnetic field. The observed MR and R-T behaviour of double layered manganite for TC1